The present invention pertains primarily to medical devices and more particularly to orthosis or splinting devices.
Generally, an orthosis or splinting device is a device used to straighten joints which have assumed abnormal positions due to decreased or absent muscle function. A large percentage of patients requiring such splinting are seen in acute care hospitals following surgery or trauma, subsequently as outpatients, or in rehabilitation centers. Dynamic or adjustable splints frequently are used to substitute for absent muscle power and to assist weak muscle power, as well as to prevent contractures, to maintain balance, to promote rest, or to mobilize specific joints. The splinting devices themselves may be required for skeletal substitution, such as to aid in fracture alignment, or to support bones and joints having pathology. They may also be used to provide muscle balance for paralyzed muscles or for divided tendons or muscles. For resting patients, splints may be used to promote wound healing of newly repaired structures, or to treat infection or relieve pain.
Dynamic splinting may generally be defined as the application on a moving part of a force which remains approximately constant as the part moves. Often it is called "active" splinting, referring to the mobility which the splint gives to the patient's joints with specific and directional controls, by providing forces which substitute for absent muscle power. This joint mobility can decrease adhesions, maintain joint function, and prevent ankylosis of the joint. In addition, this type of splinting has a physiological effect as well, for when the muscles are moving they pump away stagnant fluids which wash out the toxins and keep the tendons sliding and joints moving. Dynamic or active splinting provides constant force over a long period of time in contrast to strong, short-term pressure, similar to the principle an orthodontist uses in straightening teeth. For example, it has been found that several hours of light, steady tension is very often more successful than vigorous exercise for a few minutes, especially where contractures are present. Progressive alteration to a static splint can draw out a contracture and active dynamic splinting can aid in maintaining the correction.
In the past, it has been the general rule that a dynamic splint must contain a rigid base specifically made to fit the particular patient since it has almost always been thought that a splint that fits everyone fits no one. This static base of a dynamic splint is of primary importance in most conventional splinting and usually comprises a rigid base which is secured to the subject joint and which forms the foundation for various traction-type mechanisms which are used for tensioning the subject joint or joints. The static base of the splint provides foundation for proper (functional) alignment of joints, provides a foundation to which tractioning components may be attached, and also provides the foundation for a hinge joint. It may also be used to aid in the relaxation of any spastic muscle, to allow tissues to adapt to their new position, to protect newly repaired structures, to provide support for proximal parts for allowing increased function in distal joints or uninvolved parts, and to aid in positioning for edema control. However, it is well known that when one is constructing the static base of the splint, one must always remember that such immobilization leads to joint stiffness. This has always been one of the major drawbacks of this type of splint since once such joint stiffness has occurred, it is difficult to overcome. It has been found that it is much easier to prevent joint stiffness in the first place, than it is to overcome it once it has occurred. As will be explained in more detail hereinbelow, the present invention does not lead to such joint stiffness.
Typical of devices currently used by the medical profession include what are known as "outriggers". These devices contain a rigid support base such as that described above and have various tightening and tensioning mechanisms projecting therefrom which from time to time are adjusted to bring the abnormal joint back to a normal configuration. Such dynamic splints are typically very complex in design and constructed so as to provide specific traction with directional control. They utilize outriggers which must be very carefully and accurately placed and secured to the body of the splint since the stability and the maintenance of splint position is of prime importance. Needless to say, these outrigger devices are uncomfortable to the wearer and also require considerable attention from the skilled personnel monitoring the progress of the return of the joint to normal position.
In addition to the disadvantages of prior art orthosis or splinting devices referred to above, most devices currently used are relatively bulky and unattractive. Very often they are also uncomfortable and produce pressure sores during use. In addition, most such devices are difficult to position and even then, improper fitting is a problem in many cases since custom-making each and every device to fit each and every patient would be impossible due to the costs involved. Once positioned, most such prior art devices require almost constant monitoring to assure continued positive action, thus involving significant additional expense due to the necessity of the continued presence of skilled medical personnel.
Accordingly, it is a principle object of the present invention to provide a dynamic orthosis device which, in addition to being comfortable and easy to fit, automatically provides an active extension force which gradually decreases as the subject joint or joints assume a normal extended position.
In general, the dynamic foam orthosis of the present invention provides active forces necessary to substitute for decreased, absent, or abnormal muscle function in jointed portions of a body. It comprises a cellular foam base, a cellular foam cover, and at least one restraining strap means. The cellular foam base is contoured with a cavity adapted to mate with and partially support the body portion requiring substitute muscle forces. The cellular foam cover which is used in conjunction with the base is movable with respect to the base from a closed position in which it is in engagement with the base to an open position in which the contoured cavity of the base is exposed so as to allow the subject body portion to be placed therein. At least one restraining strap means is used for holding the cover in engagement with the base once the subject body portion has been placed in the contoured cavity of said base. Due to the properties and design of the resilient foam, the device of the present invention provides active forces on the subject body portion which automatically change as the position of the body portion changes.
Additional advantages and features of the present invention will become apparent from a reading of the detailed description of the preferred embodiment which makes reference to the following set of drawings in which: